Apparatus for dispensing sterile gas

ABSTRACT

A portable unit for sterilizing gas to cleanse it of foreign bodies, especially living microorganisms, comprising a portable frame supporting a sub-micron filter through which the gas is passed when connected between a gas source and gas utilization apparatus, for example between an oxygen source and an oxygen mask for a patient. A pressure gauge monitors the pressure developed across the sub-micron filter and is preferably calibrated in terms of filtration efficiency to provide an indication of when the filter has reached a condition for which it should be replaced. The sub-micron filter is preceded by a pressure regulator which receives gas under high pressure from a contaminated source, reduces it to a working pressure, and supplies it to the sub-micron filter at a fixed predetermined pressure value. Preferably also employed are an inlet pressure gauge for measuring the pressure of the gas supplied from the source to the pressure regulator and a flow meter and flow control through which the gas passes before it is delivered to the outlet connection to the gas utilization apparatus. In this way gas from a bulk source or an unsterilized container is rendered sterile by connection thereto of the portable gas sterilizer. The visual monitoring of the condition of the filter insures proper maintenance by replacement of the filter when needed.

United States Patent [151 3,672,129 Strople et al. [4 1 June 27, 197254] APPARATUS FOR DISPENSING 3,176,447 5/1965 STERILE GAS Omohundro etal ..5 5/279 Primary Examiner-Tim R. Miles [72] Inventors: Gordon N.trople Cherry Hill; Justin W. Assistant Examiner vincem Gifford Mills,Jr., Cinnammson, both of NJ. Attorney Howson and Howson [73] Assignee:Lif-O-Gen, Inc., Lumberton, NJ. ABSTRACT [22] Filed: March 20, 1970 Aportable unit for stenllzlng gas to cleanse it of foreign [21] AppL N -Z21, 42 bodies, especially living microorganisms, comprising a portableframe supporting a sub-micron filter through which the gas 52 us. Cl.55/270, 55/274, 55/279, 9 when g a gas 55/323, 55/356, 55/417 55/503,SSIDIG l7 uti ization apparatus, or examp e e ween an oxygen source128/185 and an oxygen mask for a patient. A pressure gauge monitors [51]Int Cl B01 d 53/30 the pressure developed across the submicron filterand is [58] H 1 d 323 350 preferably calibrated in terms of filtrationefficiency to provide an indication of when the filter has reached acondition 23/281 21 IDG 99/49 2'6l/DlG for which it should be replaced.The sub-micron filter is preceded by a pressure regulator which receivesgas under [56] References Cited high pressure from a contaminatedsource, reduces it to a working pressure, and supplies it to thesub-micron filter at a UNITED STATES PATENTS fixed predeterminedpressure value. Preferably also employed are an inlet pressure gauge formeasuring the pressure of the 3,441,020 4/1969 Wortz et al. ..l28/l46.4gas fi d f the source to the pressure regulator and a 6/ 1965 l "128/191R flow meter and flow control through which the gas passes be- 2,550,8105/ 1951 Heldbnnk Ux fore it is delivered to the outlet connection to thegas utiliza- 3,024,655 3/1962 y at mess/274 Ux tion apparatus. In thisway gas from a bulk source or an un- 3,l76,448 4/ 1965 sterilizedcontainer is rendered sterile by connection thereto 3,351,052 1 1967HCYVSOn 1 37/87 x of the portable gas sterilizer. The visual monitoringof the con- 331382 2 dition of the filter insures proper maintenance byreplacement 5 0, ee we of the filter when needed. 2,789,654 4/1957 Zurit..55/4l7 X 2,553,763 5/195] Hammon ..55/518 X 6 Claims, 4 DrawingFigures 54 p2*,;g .5 7 g Z 22 /2 26 3:0 I N "W SuB-wcnoN F LOW 1 22R*!LATOR FILTER METER W GAUGE 32 /4' u T'lLlZA Tl ON APPARATU sPATENTEDJUHN I972 SHEET 10F 2 INVENTORS. JUSTIN W. MILLS,JR. GORDON N- STROPLE ATTYS.

PATENTEuJum I972 SHEET 20F 2 FIGB. 9f 6 INVENTORSL JUSTIN W. MILL5,JR BYGORDON N. STROPLE ATTYS APPARATUS FOR DISPENSING STERILE GAS BACKGROUNDOF THE INVENTION There are a variety of applications in which it isdesired to be able to supply clean, sterile gas to some utilizationapparatus. For example, it may be desired to supply sterile oxygen,uncontaminated by living microorganisms, to an oxygen mask fortherapeutic use by a patient. In certain laboratory operations it may behighly important to remove'such small organisms from a gas whichotherwise would produce biological contamination. In many othersituations, for example in the fabrication of sensitive semi-conductordevices, it may be very important to remove even very fine particles ofcontaminants of non-living material. In addition to oxygen, other commonmaterials in which such requirements for extreme cleanliness typicallyarises include air, nitrogen, cyclopropane, nitrous oxide, carbondioxide and helium, as examples.

The copending application Ser. No. 765,044 of Gordon N. Strople andJustin W. Mills, Jr., filed Oct. 4, 1968, now abandoned, and entitledMethod and Apparatus for Sterilizing Gas Containers and Filling SameWith A Sterile Gas and of common assignee herewith, describes onepossible approach to providing such a sterile supply. of gas. Accordingto the latter application, a manufacturing process is provided by whichgas containers can be sterilized and charged with sterilized gasproducts, after which they may be packaged for shipment, ready for use,in a sterile packaged filled with a sterilizing agent. When it isdesired to utilize the sterile gas, the equip ment is removed from thepackage and is in condition to provide the necessary clean gas supply.

However, there are many situations in which this approach is notentirely satisfactory. For example, the facility at which the need forthe sterile gas arises may already be piped with bulk gas, or may havegas in standard containers readily available, in either of which cases,from the viewpoint of economics and convenience, it would be desirableto make use of the gas already available at the facility rather than toimport a new supply of sterile gas for the particular required use.

Accordingly it is an object of the invention to provide a new and usefulapparatus for providing a supply of sterile gas.

A further object is to provide such apparatus which makes use ofexisting supplies of gas, whether in standard containers or in supplypipes.

It is also an object to provide such apparatus which is reach-- SUMMARYOF THE INVENTION These and other objects of the invention are achievedby the provision of apparatus by means of which gas from a contaminatedsource is supplied to gas utilization apparatus by way of a sterilizingdispenser including a submicron filter, through which filter the gas ispassed when the unit is connected between the source and the utilizationdevice. Filter monitoring means are associated with the sub-micronfilter for providing continuous visual indications of the operatingcondition of the filtering means, whereby when it becomes inefiicientdue for example to clogging, such condition will be indicated and theoperator warned to replace the filter means with a fresh filteringelement. Preferably also employed are a pressure regulator for receivingthe impure gas through the inlet means and supplying it to thesub-micron filter at a substantially reduced pressure; an inlet pressuregauge for measuring the pressure at the inlet to provide indications ofthe contents of a gas source, particularly where the latter source is acontainer of gas; and flow metering and flow control means forcontrolling the rate of flow of the gas to the gas utilization device,and for providing simultaneous indication of the rate of such flow.

With such apparatus, for example, a piping system for unsterilizedoxygen may be provided in hospital rooms and a portable unit, itselfsterilized and constructed in accordance with the invention, may beconnected between the outlet of the piping and a patients oxygen mask tosupply the patient with a controlled rate of flow of sterilized oxygen.Similarly, where impure of unsterilized oxygen is available incontainers in a hospital, one such standard container may be installedin a patients room and a portable sterilizer constructed in accordancewith the invention connected between the output of the standardcontainer and the patients oxygen mask. Also, in a laboratory wherenitrogen is to be utilized as an inert atmosphere in certain experimentsor in actual manufacturing, for example, a sterilizing unit inaccordance with the invention may be inserted between the impure sourceof such nitrogen and the point at which the gas is to be put into use,to assure a completely uncontaminated supply of the gas. Many otherapplications will occur to one skilled in the art.

BRIEF DESCRIPTION OF FIGURES These and other objects and features of theinvention will be more readily understood from a consideration of thefollowing detailed description taken in connection with the accompanyingdrawings, in which:

FIG. 1 is a schematic block diagram illustrating a system in accordancewith the invention in one of its possible uses;

FIG. 2 is a perspective view of one form of physical embodiment of aportable unit in accordance with the invention;

FIG. 3 is a plan view of the apparatus of FIG. 2 with the outercontainer shown in phantom for greater clarity; and

FIG. 4 is an elevational view, with the casing broken away in part, toshow the interior construction of the apparatus of FIG. 2 and 3.

DESCRIPTION OF SPECIFIC EMBODIMENTS manually controllable outlet valve12, gas from which is to be supplied to gas utilization apparatus I4,which may for example comprise an oxygen mask for a medical patient. Itis assumed that, due to the presence of living organisms such asbacteria and/or non-living material in the gas in container 10,

- direct delivery of the gas from the container to the gas utilizationapparatus 14 would be undesirable because of the possible effects ofsuch organisms or other impurities upon the patient using the mask. Inaccordance with the invention, the portable sterile gas dispenser 18 isconnected between the outlet valve 12 of the standard gas cylinder andthe gas utilization apparatus 14 to provide the desired supply ofsterilized gas to the latter apparatus.

The parts of the sterile gas dispenser 18 shown in FIG. 1 are designatedby corresponding numerals in the physical embodiment of the inventionshown in FIGS. 2-4. In general, the flexible gas line 22 from the outletvalve I2 of the standard gas container 10 is connected to the inletconnector 24 for the sterile gas dispenser 18. The latter connector 24may include a primary filter consisting of a relatively coarse filtersuch as may be provided by a IO-micron metal mesh, in order to screenout any large scale foreign bodies or impurities which may happen to bepresent in the gas traversing line 22. Within the dispenser 18, the gasis supplied through the adjustable pressure regulator 26 to a sub-micronfilter 28, and thence through a flow meter 30 and a flow controlarrangement 32 integral with the flow meter to the outlet connector 34of the dispenser, from which a flexible outlet line 36 supplies asterilized gas to the gas utilization apparatus I4.

In parallel with the sub-micron filter 28 there is connected thefilter-monitoring pressure gauge 38 which continuously provides anindication of the gas-pressure differential between opposite sides ofthe filter, for reasons described in more detail hereinafter. Alsopreferably employed is an inlet pressure gauge 40 connected to the inletof the pressure regulator 26, which in the application illustratedeffectively provides a reading of the pressure of the gas in thestandard container 10, and thereby also provides an indication of thegas content of the container. Pressure regulator 26 receives the inletgas under the pressure established by the pressure in container 10, andsupplies sub-micron filter 28 with a reduced, substantially fixedpressure typically of the order of about 50 psi.

In the physical embodiment of the invention illustrated in FIGS. 2-4,and in which numerals corresponding to those in FIG. 1 representcorresponding parts, the apparatus is shown as a portable unitcomprising a frame 50 having an outer cylindrical casing 52 on which theinlet and outlet connectors 24 and 34 are mounted in conventionalmanner. The inlet connector 24 delivers gas directly to the inletpressure gauge 40, which is mounted above the top of the frame 50 andcomprises an angularly deflectable needle 42 the position of whichindicates the inlet gas pressure. The pressure regulator 26, as shown inFIGS. 3 and 4, is mounted just below the top of the cylindrical casing52. The outlet 60 of the regulator is connected by flexible tubing 62and T-connector 64 to one side of the sub-micron filter 28 and to oneside of the filter-monitoring pressure gauge 38, by means of flexibleconnectors 68 and 70 respectively.

The filter-monitoring pressure gauge 38 may consist of a commerciallyavailable type in which a piston 71 thereof moves upwardly in proportionto the differential in pressure between its inlet and outlet connectors.Flexible line 70 is connected to the inlet connector of the gauge, andthe outlet connector is connected to the flexible line 76 and thence tothe opposite side of the sub-micron filter 28 by way of the T-connector78. Accordingly, the extent to which the piston 71 of the gauge 38 risesupwardly is in proportion to the pressure developed across thesub-micron filter 28 by the flow of gas through it.

Piston 71 is rendered visible by means of a transparent window 80, andindicia or color ranges may be provided on or adjacent the window toprovide the viewer with an indication of when the pressure across thesub-micron filter is of a low, medium or high value. When the filter isnew, the pressure across it will be lowest, but as it begins toaccumulate contaminants in its pores the pressure across it will riseinto the region of medium pressure, and finally into the region ofrelatively high pressure, at which time the filter should be replacedsince it is no longer efficient in performing its intended task ofremoving microbes and very fine impurities from the gas and, inaddition, is preventing the desired relatively free flow of gas throughit.

The flow meter 30 is also of conventional form and is mounted generallybelow the top surface of the cylindrical casing 52 with its calibratedscale visible through the side cylindrical surface of the frame. Gasflow to the flow meter is provided from T-connector 78 by way offlexible line 86, and the outlet 88 of the flow meter is connecteddirectly to the outlet connector 34 of the sterile gas dispenser. Theflow control 89 consists in this embodiment of a rotatable knob,connected by a shaft to a suitable flow control arrangement, not shownin detail since the apparatus is well-known and commercially available.

In operation, the sterile gas dispenser 18 is constructed and mounted asshown, and is preferably sterilized and shipped in a package containinga sterilizing gas atmosphere to the location at which it is to be used.When the equipment is removed from its sterile package, the outletconnector 34 thereof is connected to the utilization device, such as anoxygen mask for example. The inlet connector 24 is connected to a sourceof gas, which as mentioned above may be standard gas piping or astandard gas container. The gas source will then be turned on, and theinlet pressure gauge 40 will indicate directly the pressure of the gasfrom the source, providing continuous monitoring thereof. This is ofparticular interest where the source of gas is a standard cylinder inwhich the amount of gas in the cylinder is constantly being depleted,the inlet pressure serving as an indication of the contents of thecontainer to provide immediate information as to how much gas remainsand whether, for example, another container of gas will be required inthe near future. The gas then flows through the pressure regulator 26,wherein the pressure is reduced to the desired delivery level, typicallyabout 50 psi. The gas then flows through the sub-micron filter 28,containing pores of sub-micron size, which will remove microscopicliving organisms from the gas stream, together with any remainingnon-living impurity particles of small size. The filter-monitoringpressure gauge 38 meanwhile monitors the differential pressure acrossthe sub-micron filter; the operator is preferably provided withmaintenance instructions directing him to replace the filter with a newone if the pressure differential indicated by gauge 38 rises above apredetermined level. The flow control knob 89 is adjusted to provide therate of flow desired for the particular application, as indicated by theflow meter 30.

The particular form of sub-micron filter utilized in the present examplecan be seen in FIG. 4. It will be seen that the filter comprises twoopposed ceramic disks 91 and 92 having coarse holes through them,between which the sub-micron filter element 93 is clamped by means ofthe three clamping knobs 95, which can be loosened to remove the filterelement. In order to enable convenient changing of the filter, a portion96 of the generally cylindrical supporting frame 50 located below theoutlet connector 34 is hingedly connected at 97 to the upper portionthereof, and normally held in the closed position shown by means of anappropriate latching arrangement 98. When, as indicated by a relativelyhigh pressure reading on the filter monitoring pressure gauge 38, it istime to change the sub-micron filter, the entire unit is preferablydisconnected from service and, if required, replaced temporarily with asubstitute unit; the removed unit is then opened by dropping the lowerhinged portion of the container, thereby to expose completely thesub-micron filter and its three clamping knobs. By loosening theclamping knobs and opening the filter housing, the filter element 93 iseasily replaced. This procedure is preferably accomplished in such a wayas to assure resterilization of the interior surfaces of the filter,which may be accomplished by gas sterilization, ultrasonics orultraviolet as examples. Such techniques are well known in the art andhence need not be described here in detail. Suffice it to indicate that,after sterilization, the unit is reassembled, the hinged bottom closedagain, and the unit placed back into service when required.

Accordingly, there has been provided a unit, preferably easily portable,which can readily be connected and disconnected to provide sterilizationof gas from an unsterile gas source, to provide monitoring of the inletpressure and the outlet gas flow rate, and at the same time to indicatevisually when a condition has been reached in which the sub-micronfilter should be replaced. In this way, a supply of sterilized gas ismade possible in facilities in which piping of bulk, unsterilized gas,or quantities of unsterilized gas in standard containers, are available.

While the invention has been described in the interest of definitenesswith particular regard to specific embodiments thereof, it will beunderstood that it may be embodied in a variety of ways diverse fromthose specifically shown and described without departing from theinvention.

What is claimed is: 1. Apparatus for sterilizing a flow of gas from asource of gas to a gas utilization means comprising:

gas inlet means detachably connectable to said gas source to receive gasfrom said source when connected thereto;

adjustable pressure regulator means supplied with said gas from saidsource, said pressure regulator means having an outlet, said pressureregulating means being operable for producing a substantially fixedpressure of said gas at the outlet of said regulator means;

pressure measuring means connected to said inlet means for indicatingthe pressure of said gas at said inlet means;

sub-micron filter means supplied with said gas from said regulator meansfor filtering from said gas foreign-body particles of sub-micron size,said filter means having a 5 pore size operable to remove all livingmicroorganisms from said gas to thereby sterilize said gas, saidsub-micron filter means being readily removable and replaceable;

flow control means supplied with said gas from said submicron filtermeans for enabling adjustment of the volume rate of flow of said gastherethrough;

flow metering means for measuring the volume rate of flow of said gasthrough said flow control means;

gas outlet means detachably connectable to gas utilization means, forsupplying said gas from said flow metering means to said utilizationmeans when connected thereto;

filter monitoring means operatively associated with said sub-micronfilter means for providing indications of the operating condition ofsaid sub-micron filter means; and

portable frame means mounting and supporting said gas inlet means, saidpressure regulator means, said pressure measuring means, said sub-micronfilter means, said filter monitoring means, said flow control means,said flow metering means, and said gas outlet means as an integralportable unit, whereby said inlet means and said outlet means may bereadily connected to different gas sources and different gas utilizationmeans respectively.

2. The apparatus of claim 1, wherein said filter monitoring meansassociated with said filter means provides visual indications of theoperating condition of said filter means, and means mounting said filtermeans for ready removal and replacement whereby said filter means may bereplaced when said filter monitoring means indicates that said filtermeans is no longer operating adequately.

3. The apparatus of claim 2, in which said filter monitoring meanscomprises means for continuously sensing the gas pressure drop acrosssaid filter means and means visually indicating the magnitude of saidpressure drop.

4. The apparatus of claim 3, in which said mounting means comprises apair of opposed multiply-apertured plates, one on each side of saidfilter means, and releasable clamping means for clamping said platestogether with said filter means between them.

5. The apparatus of claim 2 wherein said pressure measuring meansprovides a visual indication of the magnitude of the gas pressure atsaid inlet means.

6. The apparatus of claim 2 wherein said flow metering means providesvisual indications of the rate of flow of gas from said outlet means.

1. Apparatus for sterilizing a flow of gas from a source of gas to a gasutilization means comprising: gas inlet means detachably connectable tosaid gas source to receive gas from said source when connected thereto;adjustable pressure regulator means supplied with said gas from saidsource, said pressure regulator means having an outlet, said pressureregulating means being operable for producing a substantially fixedpressure of said gas at the outlet of said regulator means; pressuremeasuring means connected to said inlet means for indicating thepressure of said gas at said inlet means; sub-micron filter meanssupplied with said gas from said regulator means for filtering from saidgas foreign-body particles of sub-micron size, said filter means havinga pore size operable to remove all living microorganisms from said gasto thereby sterilize said gas, said sub-micron filter means beingreadily removable and replaceable; flow control means supplied with saidgas from said sub-micron filter means for enabling adjustment of thevolume rate of flow of said gas therethrough; flow metering means formeasuring the volume rate of flow of said gas through said flow controlmeans; gas oUtlet means detachably connectable to gas utilization means,for supplying said gas from said flow metering means to said utilizationmeans when connected thereto; filter monitoring means operativelyassociated with said submicron filter means for providing indications ofthe operating condition of said sub-micron filter means; and portableframe means mounting and supporting said gas inlet means, said pressureregulator means, said pressure measuring means, said sub-micron filtermeans, said filter monitoring means, said flow control means, said flowmetering means, and said gas outlet means as an integral portable unit,whereby said inlet means and said outlet means may be readily connectedto different gas sources and different gas utilization meansrespectively.
 2. The apparatus of claim 1, wherein said filtermonitoring means associated with said filter means provides visualindications of the operating condition of said filter means, and meansmounting said filter means for ready removal and replacement wherebysaid filter means may be replaced when said filter monitoring meansindicates that said filter means is no longer operating adequately. 3.The apparatus of claim 2, in which said filter monitoring meanscomprises means for continuously sensing the gas pressure drop acrosssaid filter means and means visually indicating the magnitude of saidpressure drop.
 4. The apparatus of claim 3, in which said mounting meanscomprises a pair of opposed multiply-apertured plates, one on each sideof said filter means, and releasable clamping means for clamping saidplates together with said filter means between them.
 5. The apparatus ofclaim 2 wherein said pressure measuring means provides a visualindication of the magnitude of the gas pressure at said inlet means. 6.The apparatus of claim 2 wherein said flow metering means providesvisual indications of the rate of flow of gas from said outlet means.